We have a cannon digital rebel xt and two photogenic powerlight 1250. One power light is a soft box and the other is a strobe with an umbrella. The problem is I can not get the strobe to fire when the lights detect the flash from the camera. The strobe just goes off and then back on kinda like turning a light switch on and off. Most of the photos turn out rather dark. Is there a resource or manual for the lights? Does anyone know how to fix this problem?